Control channel structure design to support V2X traffic

ABSTRACT

There is provided an apparatus, said apparatus comprising means for providing first control information using a first control channel and at least second control information using a second control channel, wherein the first control information comprises at least an indication of resource reservation for an associated data channel and the second control information comprises at least transmission format information for the associated data channel, wherein the associated data channel comprises periodic or aperiodic data traffic.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a National Stage Entry of InternationalPatent Application No. PCT/CN2018/108481, filed Sep. 28, 2018, entitled“Control Channel Structure Design To Support V2X Traffic,” the entirecontents of each of which are hereby incorporated herein by reference intheir entireties for all purposes.

FIELD

The present application relates to a method, apparatus, system andcomputer program and in particular but not exclusively to controlchannel structures for periodic and aperiodic vehicle-to-everything(V2X) traffic.

BACKGROUND

A communication system can be seen as a facility that enablescommunication sessions between two or more entities such as userterminals, base stations and/or other nodes by providing carriersbetween the various entities involved in the communications path. Acommunication system can be provided for example by means of acommunication network and one or more compatible communication devices.The communication sessions may comprise, for example, communication ofdata for carrying communications such as voice, video, electronic mail(email), text message, multimedia and/or content data and so on.Non-limiting examples of services provided comprise two-way or multi-waycalls, data communication or multimedia services and access to a datanetwork system, such as the Internet.

In a wireless communication system at least a part of a communicationsession between at least two stations occurs over a wireless link.Examples of wireless systems comprise public land mobile networks(PLMN), satellite based communication systems and different wirelesslocal networks, for example wireless local area networks (WLAN). Thewireless systems can typically be divided into cells, and are thereforeoften referred to as cellular systems.

A user can access the communication system by means of an appropriatecommunication device or terminal. A communication device of a user maybe referred to as user equipment (UE) or user device. A communicationdevice is provided with an appropriate signal receiving and transmittingapparatus for enabling communications, for example enabling access to acommunication network or communications directly with other users. Thecommunication device may access a carrier provided by a station, forexample a base station of a cell, and transmit and/or receivecommunications on the carrier.

The communication system and associated devices typically operate inaccordance with a given standard or specification which sets out whatthe various entities associated with the system are permitted to do andhow that should be achieved. Communication protocols and/or parameterswhich shall be used for the connection are also typically defined. Oneexample of a communications system is UTRAN (3G radio). Other examplesof communication systems are the long-term evolution (LTE) of theUniversal Mobile Telecommunications System (UMTS) radio-accesstechnology and so-called 5G or New Radio (NR) networks. NR is beingstandardized by the 3rd Generation Partnership Project (3GPP).

SUMMARY

In a first aspect there is provided an apparatus, said apparatuscomprising means for providing first control information using a firstcontrol channel and at least second control information using a secondcontrol channel, wherein the first control information comprises atleast an indication of resource reservation for an associated datachannel and the second control information comprises at leasttransmission format information for the associated data channel, whereinthe associated data channel comprises periodic or aperiodic datatraffic.

The apparatus may comprise means for providing the first controlinformation and the second control information using the second controlchannel.

The first control information may comprise at least one of an indicationof data periodicity, data packet information indicating quality ofservice requirement, resource reservation information and resourceallocation information.

The second control information may comprise at least one of modulationand coding scheme (MCS) information, multi-antenna transmission relatedinformation and destination address information.

At least one of the first control information and the second controlinformation may comprise at least one of data packet retransmissioninformation and demodulation reference configuration information for theassociated data channel.

The apparatus may comprise means for, when the associated data channelcomprises periodic data traffic and there is no data transmission in acurrent period, providing first control information using the firstcontrol channel, wherein the first control information comprises anindication of the absence of data transmission in the current period.

The apparatus may comprise means for, when the associated data channelcomprises periodic data traffic and there is data transmission in acurrent period, providing the second control channel or the firstcontrol channel and the second control channel with the associated datachannel.

The apparatus may comprise means for, when the associated data channelcomprises aperiodic data traffic, providing the first control channel intime resources preceding the associated data channel.

In a second aspect there is provided an apparatus, said apparatuscomprising means for receiving first control information using a firstcontrol channel and at least second control information using a secondcontrol channel, wherein the first control information comprises atleast an indication of resource reservation for an associated datachannel and the second control information comprises at leasttransmission format information for the associated data channel, whereinthe associated data channel comprises periodic or aperiodic datatraffic.

The apparatus may comprise means for receiving the first controlinformation and the second control information using the second controlchannel.

The first control information may comprise at least one of an indicationof data periodicity, data packet information indicating quality ofservice requirement, resource reservation information and resourceallocation information.

The second control information comprises at least one of modulation andcoding scheme (MCS) information, multi-antenna transmission relatedinformation and destination address information.

At least one of the first control information and the second controlinformation may comprise at least one of data packet retransmissioninformation and demodulation reference configuration information for theassociated data channel.

The apparatus may comprise means for, when the associated data channelcomprises periodic data traffic and there is no data transmission in acurrent period, receiving first control information using the firstchannel, wherein the first control information comprises an indicationof the absence of data transmission in the current period.

The apparatus may comprise means for, when the associated data channelcomprises periodic data traffic and there is data transmission in acurrent period, receiving the second control channel or the firstcontrol channel and the second control channel with the associated datachannel.

The apparatus may comprise means for, when the associated data channelcomprises aperiodic data traffic, receiving the first control channel intime resources preceding the associated data channel.

In a third aspect there is provided a method comprising for providingfirst control information using a first control channel and at leastsecond control information using a second control channel, wherein thefirst control information comprises at least an indication of resourcereservation for an associated data channel and the second controlinformation comprises at least transmission format information for theassociated data channel, wherein the associated data channel comprisesperiodic or aperiodic data traffic.

The method may comprise providing the first control information and thesecond control information using the second control channel.

The first control information may comprise at least one of an indicationof data periodicity, data packet information indicating quality ofservice requirement, resource reservation information and resourceallocation information.

The second control information may comprise at least one of modulationand coding scheme (MCS) information, multi-antenna transmission relatedinformation and destination address information.

At least one of the first control information and the second controlinformation may comprise at least one of data packet retransmissioninformation and demodulation reference configuration information for theassociated data channel.

The method may comprise, when the associated data channel comprisesperiodic data traffic and there is no data transmission in a currentperiod, providing first control information using the first controlchannel, wherein the first control information comprises an indicationof the absence of data transmission in the current period.

The method may comprise, when the associated data channel comprisesperiodic data traffic and there is data transmission in a currentperiod, providing the second control channel or the first controlchannel and the second control channel with the associated data channel.

The method may comprise, when the associated data channel comprisesaperiodic data traffic, providing the first control channel in timeresources preceding the associated data channel.

In a fourth aspect there is provided a method comprising receiving firstcontrol information using a first control channel and at least secondcontrol information using a second control channel, wherein the firstcontrol information comprises at least an indication of resourcereservation for an associated data channel and the second controlinformation comprises at least transmission format information for theassociated data channel, wherein the associated data channel comprisesperiodic or aperiodic data traffic.

The method may comprise receiving the first control information and thesecond control information using the second control channel.

The first control information may comprise at least one of an indicationof data periodicity, data packet information indicating quality ofservice requirement, resource reservation information and resourceallocation information.

The second control information comprises at least one of modulation andcoding scheme (MCS) information, multi-antenna transmission relatedinformation and destination address information.

At least one of the first control information and the second controlinformation may comprise at least one of data packet retransmissioninformation and demodulation reference configuration information for theassociated data channel.

The method may comprise, when the associated data channel comprisesperiodic data traffic and there is no data transmission in a currentperiod, receiving first control information using the first channel,wherein the first control information comprises an indication of theabsence of data transmission in the current period.

The method may comprise, when the associated data channel comprisesperiodic data traffic and there is data transmission in a currentperiod, receiving the second control channel or the first controlchannel and the second control channel with the associated data channel.

The method may comprise, when the associated data channel comprisesaperiodic data traffic, receiving the first control channel in timeresources preceding the associated data channel.

In a fifth aspect there is provided an apparatus comprising: at leastone processor and at least one memory including a computer program code,the at least one memory and computer program code configured to, withthe at least one processor, cause the apparatus at least to:

provide first control information using a first control channel and atleast second control information using a second control channel, whereinthe first control information comprises at least an indication ofresource reservation for an associated data channel and the secondcontrol information comprises at least transmission format informationfor the associated data channel, wherein the associated data channelcomprises periodic or aperiodic data traffic.

The apparatus may be configured to provide the first control informationand the second control information using the second control channel.

The first control information may comprise at least one of an indicationof data periodicity, data packet information indicating quality ofservice requirement, resource reservation information and resourceallocation information.

The second control information may comprise at least one of modulationand coding scheme (MCS) information, multi-antenna transmission relatedinformation and destination address information.

At least one of the first control information and the second controlinformation may comprise at least one of data packet retransmissioninformation and demodulation reference configuration information for theassociated data channel.

The apparatus may be configured to, when the associated data channelcomprises periodic data traffic and there is no data transmission in acurrent period, provide first control information using the firstcontrol channel, wherein the first control information comprises anindication of the absence of data transmission in the current period.

The apparatus may be configured to, when the associated data channelcomprises periodic data traffic and there is data transmission in acurrent period, provide the second control channel or the first controlchannel and the second control channel with the associated data channel.

The apparatus may be configured to, when the associated data channelcomprises aperiodic data traffic, providing the first control channel intime resources preceding the associated data channel.

In a sixth aspect there is provided an apparatus comprising: at leastone processor and at least one memory including a computer program code,the at least one memory and computer program code configured to, withthe at least one processor, cause the apparatus at least to:

receive first control information using a first control channel and atleast second control information using a second control channel, whereinthe first control information comprises at least an indication ofresource reservation for an associated data channel and the secondcontrol information comprises at least transmission format informationfor the associated data channel, wherein the associated data channelcomprises periodic or aperiodic data traffic.

The apparatus may be configured to receive the first control informationand the second control information using the second control channel.

The first control information may comprise at least one of an indicationof data periodicity, data packet information indicating quality ofservice requirement, resource reservation information and resourceallocation information.

The second control information comprises at least one of modulation andcoding scheme (MCS) information, multi-antenna transmission relatedinformation and destination address information.

At least one of the first control information and the second controlinformation may comprise at least one of data packet retransmissioninformation and demodulation reference configuration information for theassociated data channel.

The apparatus may be configured to, when the associated data channelcomprises periodic data traffic and there is no data transmission in acurrent period, receive first control information using the firstchannel, wherein the first control information comprises an indicationof the absence of data transmission in the current period.

The apparatus may be configured to, when the associated data channelcomprises periodic data traffic and there is data transmission in acurrent period, receive the second control channel or the first controlchannel and the second control channel with the associated data channel.

The apparatus may be configured to, when the associated data channelcomprises aperiodic data traffic, receive the first control channel intime resources preceding the associated data channel.

In a seventh aspect there is provided computer readable mediumcomprising program instructions for causing an apparatus to perform atleast the following:

providing first control information using a first control channel and atleast second control information using a second control channel, whereinthe first control information comprises at least an indication ofresource reservation for an associated data channel and the secondcontrol information comprises at least transmission format informationfor the associated data channel, wherein the associated data channelcomprises periodic or aperiodic data traffic.

The apparatus may be caused to perform providing the first controlinformation and the second control information using the second controlchannel.

The first control information may comprise at least one of an indicationof data periodicity, data packet information indicating quality ofservice requirement, resource reservation information and resourceallocation information.

The second control information may comprise at least one of modulationand coding scheme (MCS) information, multi-antenna transmission relatedinformation and destination address information.

At least one of the first control information and the second controlinformation may comprise at least one of data packet retransmissioninformation and demodulation reference configuration information for theassociated data channel.

The apparatus may be caused to perform, when the associated data channelcomprises periodic data traffic and there is no data transmission in acurrent period, providing first control information using the firstcontrol channel, wherein the first control information comprises anindication of the absence of data transmission in the current period.

The apparatus may be caused to perform, when the associated data channelcomprises periodic data traffic and there is data transmission in acurrent period, providing the second control channel or the firstcontrol channel and the second control channel with the associated datachannel.

The apparatus may be caused to perform, when the associated data channelcomprises aperiodic data traffic, providing the first control channel intime resources preceding the associated data channel.

In an eighth aspect there is provided a computer readable mediumcomprising program instructions for causing an apparatus to perform atleast the following:

receiving first control information using a first control channel and atleast second control information using a second control channel, whereinthe first control information comprises at least an indication ofresource reservation for an associated data channel and the secondcontrol information comprises at least transmission format informationfor the associated data channel, wherein the associated data channelcomprises periodic or aperiodic data traffic.

The apparatus may be caused to perform receiving the first controlinformation and the second control information using the second controlchannel.

The first control information may comprise at least one of an indicationof data periodicity, data packet information indicating quality ofservice requirement, resource reservation information and resourceallocation information.

The second control information comprises at least one of modulation andcoding scheme (MCS) information, multi-antenna transmission relatedinformation and destination address information.

At least one of the first control information and the second controlinformation may comprise at least one of data packet retransmissioninformation and demodulation reference configuration information for theassociated data channel.

The apparatus may be caused to perform, when the associated data channelcomprises periodic data traffic and there is no data transmission in acurrent period, receiving first control information using the firstchannel, wherein the first control information comprises an indicationof the absence of data transmission in the current period.

The apparatus may be caused to perform, when the associated data channelcomprises periodic data traffic and there is data transmission in acurrent period, receiving the second control channel or the firstcontrol channel and the second control channel with the associated datachannel.

The apparatus may be caused to perform, when the associated data channelcomprises aperiodic data traffic, receiving the first control channel intime resources preceding the associated data channel.

In a ninth aspect there is provided a non-transitory computer readablemedium comprising program instructions for causing an apparatus toperform at least the method according to the third aspect or a methodaccording to the fourth aspect.

In the above, many different example embodiments have been described. Itshould be appreciated that further example embodiments may be providedby the combination of any two or more of the example embodimentsdescribed above.

DESCRIPTION OF FIGURES

Embodiments will now be described, by way of example only, withreference to the accompanying Figures in which:

FIG. 1 shows a schematic diagram of an example communication systemcomprising a base station and a plurality of communication devices;

FIG. 2 shows a schematic diagram of an example mobile communicationdevice;

FIG. 3 shows a schematic diagram of an example control apparatus;

FIG. 4 shows a schematic diagram of a channel structure;

FIG. 5 shows a flowchart of a method according to an example;

FIG. 6 shows a flowchart of a method according to an example;

FIG. 7 shows a schematic diagram of a channel structure according to anexample;

FIG. 8 shows a schematic diagram of a channel structure according to anexample;

FIG. 9 shows a schematic diagram of a channel structure according to anexample;

FIG. 10 shows a schematic diagram of a channel structure according to anexample.

DETAILED DESCRIPTION

Before explaining in detail the example embodiments, certain generalprinciples of a wireless communication system and mobile communicationdevices are briefly explained with reference to FIGS. 1 to 3 to assistin understanding the technology underlying the described examples.

In a wireless communication system 100, such as that shown in FIG. 1,mobile communication devices or user equipment (UE) 102, 104, 105 areprovided wireless access via at least one base station or similarwireless transmitting and/or receiving node or point. Base stations aretypically controlled by at least one appropriate controller apparatus,so as to enable operation thereof and management of mobile communicationdevices in communication with the base stations. The controllerapparatus may be located in a radio access network (e.g. wirelesscommunication system 100) or in a core network (CN) (not shown) and maybe implemented as one central apparatus or its functionality may bedistributed over several apparatuses. The controller apparatus may bepart of the base station and/or provided by a separate entity such as aRadio Network Controller. In FIG. 1 control apparatus 108 and 109 areshown to control the respective macro level base stations 106 and 107.The control apparatus of a base station can be interconnected with othercontrol entities. The control apparatus is typically provided withmemory capacity and at least one data processor. The control apparatusand functions may be distributed between a plurality of control units.In some systems, the control apparatus may additionally or alternativelybe provided in a radio network controller.

In FIG. 1 base stations 106 and 107 are shown as connected to a widercommunications network 113 via gateway 112. A further gateway functionmay be provided to connect to another network.

The smaller base stations 116, 118 and 120 may also be connected to thenetwork 113, for example by a separate gateway function and/or via thecontrollers of the macro level stations. The base stations 116, 118 and120 may be pico or femto level base stations or the like. In theexample, stations 116 and 118 are connected via a gateway 111 whilststation 120 connects via the controller apparatus 108. In some exampleembodiments, the smaller stations may not be provided. Smaller basestations 116, 118 and 120 may be part of a second network, for exampleWLAN and may be WLAN Aps.

The communication devices 102, 104, 105 may access the communicationsystem based on various access techniques, such as code divisionmultiple access (CDMA), or wideband CDMA (WCDMA). Other non-limitingexamples comprise time division multiple access (TDMA), frequencydivision multiple access (FDMA) and various schemes thereof such as theinterleaved frequency division multiple access (IFDMA), single carrierfrequency division multiple access (SC-FDMA) and orthogonal frequencydivision multiple access (OFDMA), space division multiple access (SDMA)and so on.

An example of wireless communication systems are architecturesstandardized by the 3^(rd) Generation Partnership Project (3GPP). Alatest 3GPP based development is often referred to as the long termevolution (LTE) of the Universal Mobile Telecommunications System (UMTS)radio-access technology. The various development stages of the 3GPPspecifications are referred to as releases. More recent developments ofthe LTE are often referred to as LTE Advanced (LTE-A). The LTE (LTE-A)employs a radio mobile architecture known as the Evolved UniversalTerrestrial Radio Access Network (E-UTRAN) and a core network known asthe Evolved Packet Core (EPC). Base stations of such systems are knownas evolved or enhanced Node Bs (eNBs) and provide E-UTRAN features suchas user plane Packet Data Convergence/Radio Link Control/Medium AccessControl/Physical layer protocol (PDCP/RLC/MAC/PHY) and control planeRadio Resource Control (RRC) protocol terminations towards thecommunication devices. Other examples of radio access system comprisethose provided by base stations of systems that are based ontechnologies such as wireless local area network (WLAN) and/or WiMax(Worldwide Interoperability for Microwave Access). A base station canprovide coverage for an entire cell or similar radio service area. Corenetwork elements include Mobility Management Entity (MME), ServingGateway (S-GW) and Packet Gateway (P-GW).

An example of a suitable communications system is the 5G or NR concept.Network architecture in NR may be similar to that of LTE-advanced. Basestations of NR systems may be known as next generation Node Bs (gNBs).Changes to the network architecture may depend on the need to supportvarious radio technologies and finer QoS support, and some on-demandrequirements for e.g. QoS levels to support QoE of user point of view.Also network aware services and applications, and service andapplication aware networks may bring changes to the architecture. Thoseare related to Information Centric Network (ICN) and User-CentricContent Delivery Network (UC-CDN) approaches. NR may use multipleinput-multiple output (MIMO) antennas, many more base stations or nodesthan the LTE (a so-called small cell concept), including macro sitesoperating in co-operation with smaller stations and perhaps alsoemploying a variety of radio technologies for better coverage andenhanced data rates.

Future networks may utilise network functions virtualization (NFV) whichis a network architecture concept that proposes virtualizing networknode functions into “building blocks” or entities that may beoperationally connected or linked together to provide services. Avirtualized network function (VNF) may comprise one or more virtualmachines running computer program codes using standard or general typeservers instead of customized hardware. Cloud computing or data storagemay also be utilized. In radio communications this may mean nodeoperations to be carried out, at least partly, in a server, host or nodeoperationally coupled to a remote radio head. It is also possible thatnode operations will be distributed among a plurality of servers, nodesor hosts. It should also be understood that the distribution of labourbetween core network operations and base station operations may differfrom that of the LTE or even be non-existent.

An example embodiment 5G core network (CN) comprises functionalentities. The CN is connected to a UE via the radio access network(RAN). An UPF (User Plane Function) whose role is called PSA (PDUSession Anchor) may be responsible for forwarding frames back and forthbetween the DN (data network) and the tunnels established over the 5Gtowards the UE(s) exchanging traffic with the DN.

The UPF is controlled by an SMF (Session Management Function) thatreceives policies from a PCF (Policy Control Function). The CN may alsoinclude an AMF (Access & Mobility Function).

A possible mobile communication device will now be described in moredetail with reference to FIG. 2 showing a schematic, partially sectionedview of a communication device 200. Such a communication device is oftenreferred to as user equipment (UE) or terminal. An appropriate mobilecommunication device may be provided by any device capable of sendingand receiving radio signals. Non-limiting examples comprise a mobilestation (MS) or mobile device such as a mobile phone or what is known asa ‘smart phone’, a computer provided with a wireless interface card orother wireless interface facility (e.g., USB dongle), personal dataassistant (PDA) or a tablet provided with wireless communicationcapabilities, or any combinations of these or the like. A mobilecommunication device may provide, for example, communication of data forcarrying communications such as voice, electronic mail (email), textmessage, multimedia and so on. Users may thus be offered and providednumerous services via their communication devices. Non-limiting examplesof these services comprise two-way or multi-way calls, datacommunication or multimedia services or simply an access to a datacommunications network system, such as the Internet. Users may also beprovided broadcast or multicast data. Non-limiting examples of thecontent comprise downloads, television and radio programs, videos,advertisements, various alerts and other information.

A mobile device is typically provided with at least one data processingentity 201, at least one memory 202 and other possible components 203for use in software and hardware aided execution of tasks it is designedto perform, including control of access to and communications withaccess systems and other communication devices. The data processing,storage and other relevant control apparatus can be provided on anappropriate circuit board and/or in chipsets. This feature is denoted byreference 204. The user may control the operation of the mobile deviceby means of a suitable user interface such as key pad 205, voicecommands, touch sensitive screen or pad, combinations thereof or thelike. A display 208, a speaker and a microphone can be also provided.Furthermore, a mobile communication device may comprise appropriateconnectors (either wired or wireless) to other devices and/or forconnecting external accessories, for example hands-free equipment,thereto.

The mobile device 200 may receive signals over an air or radio interface207 via appropriate apparatus for receiving and may transmit signals viaappropriate apparatus for transmitting radio signals. In FIG. 2transceiver apparatus is designated schematically by block 206. Thetransceiver apparatus 206 may be provided for example by means of aradio part and associated antenna arrangement. The antenna arrangementmay be arranged internally or externally to the mobile device.

FIG. 3 shows an example of a control apparatus for a communicationsystem, for example to be coupled to and/or for controlling a station ofan access system, such as a RAN node, e.g. a base station, eNB or gNB, arelay node or a core network node such as an MME or S-GW or P-GW, or acore network function such as AMF/SMF, or a server or host. The methodmay be implanted in a single control apparatus or across more than onecontrol apparatus. The control apparatus may be integrated with orexternal to a node or module of a core network or RAN. In some exampleembodiments, base stations comprise a separate control apparatus unit ormodule. In other example embodiments, the control apparatus can beanother network element such as a radio network controller or a spectrumcontroller. In some example embodiments, each base station may have sucha control apparatus as well as a control apparatus being provided in aradio network controller. The control apparatus 300 can be arranged toprovide control on communications in the service area of the system. Thecontrol apparatus 300 comprises at least one memory 301, at least onedata processing unit 302, 303 and an input/output interface 304. Via theinterface the control apparatus can be coupled to a receiver and atransmitter of the base station. The receiver and/or the transmitter maybe implemented as a radio front end or a remote radio head.

LTE V2X sidelink has been defined in LTE Release 14 to support directcommunication of basic road safety services (e.g. vehicle statusinformation such as position, speed and heading etc.) between vehicleand vehicle/pedestrian/infrastructure. In LTE Release 15, V2X sidelinkwas further enhanced with the features of carrier aggregation, higherorder modulation and latency reduction to support more diversifiedservices and more stringent service requirements.

In LTE V2X Release 14/15, the involved physical channels includephysical sidelink control channel (PSCCH) and physical sidelink sharedchannel (PSSCH) for control message and data traffic, respectively. InLTE V2X design, PSCCH and the associated PSSCH are transmitted over thesame time resources using non-overlapping (adjacent or non-adjacent)frequency resources, as shown in FIG. 4. The control channel of PSCCHconveys at least the information necessary to decode the associatedPSSCH. PSCCH may indicate the resource reservation for the next periodwhich facilitates efficient resource allocation for periodic V2Xtraffic. However, even in the case of resource reservation, V2Xtransmissions in the next period may be absent e.g. due to congestioncontrol by channel occupation ratio (CR)/channel busy ratio (CBR)measurements.

In LTE V2X Release 14/15, sensing based resource (re)selection andreservation are applied in V2X sidelink mode 4 (i.e. UE autonomousresource selection mode) to avoid resource selection collisions as muchas possible.

Once a UE has a packet to transmit and MAC instructs PHY layer to makecandidate resource selection to report to MAC for resource selection,the UE performs the candidate resource subset selection procedure basedon the channel sensing results, where the sensing UE decodes the PSCCHof the sensed Ues to acquire information such as packet priority,resource reservation information and control CRC bits (to determine DMRSof associated PSSCH). The sensing UE performs the measurement of PSSCHreference single received power (RSRP) to determine whether to excludethe candidate resource. The UE ranks the remaining resources based onthe energy measurement (sidelink received signal strength indicator(S-RSSI)) and reports the candidate resources with least energymeasurement.

The existing LTE V2X design of control/data channel structure andsemi-persistent transmission (SPT) with channel sensing and reservationmechanism is tailored to periodic V2X traffic. However, in NR V2X, theremay be more diverse V2X traffic types including both periodic V2Xtraffic and aperiodic V2X traffic.

For spectrum efficiency, periodic and aperiodic V2X traffic types maycoexist in the same resource pool. The LTE V2X design of control/datachannel structure and SPT mechanism may not work well for aperiodic V2Xtraffic because of the unpredictable interference due to the aperiodicnature.

The following aims to provide a new physical channel structure andmechanisms. In particular, unified sidelink physical channel structureand mechanisms may flexibly support aperiodic V2X traffic and periodicV2X traffic is provided.

FIG. 5 shows a method which may be used to provide a unified sidelinkphysical channel structure.

In a first step, S1, the method comprises providing first controlinformation using a first control channel, wherein the first controlinformation comprises at least an indication of resource reservation foran associated data channel.

In a second step, S2, the method comprises providing at least secondcontrol information using a second control channel, wherein the secondcontrol information comprises at least transmission format informationfor the associated data channel.

The associated data channel comprises periodic or aperiodic datatraffic.

The method may be performed by user equipment.

FIG. 6 shows a method which may be used to provide a unified sidelinkphysical channel structure. The method may be performed by a userequipment or a network entity.

In a first step, T1, the method comprises receiving first controlinformation using a first control channel, wherein the first controlinformation comprises at least an indication of resource reservationsfor an associated data channel wherein

In a second step, T2, the method comprises receiving at least secondcontrol information using a second control channel, wherein the secondcontrol information comprises at least transmission format informationfor the associated data channel.

The associated data channel comprises periodic or aperiodic datatraffic.

A method as described with reference to FIGS. 5 and 6 may provide aunified sidelink physical control channel design to assist efficientphysical data channel operations for scheduling assignment and resourceallocation for periodic traffic and aperiodic traffic types.

The first and second control information may comprise sidelink controlinformation.

In the method as described with reference to FIGS. 5 and 6, sidelinkcontrol information (SCI) is divided into two parts, first controlinformation and second control information (termed SCI-1 and SCI-2respectively).

The first control information and the second control information areconveyed (provided) using a first control channel (PSCCH format 1) and asecond control channel (PSCCH format 2), respectively. The first controlchannel and the second control channel may be denoted by PSCCH-1 andPSCCH-2. This sidelink physical control channel design may assist datadecoding and resource allocation of associated physical sidelink sharedchannel (PSSCH) for both periodic traffic and aperiodic traffic.

The channel PSCCH-1 may be used for resource allocation and/orreservation for the data-carrying PSSCH, i.e. an indication of resourcereservation for an associated data channel.

For periodic traffic, PSCCH-1 indicates resource allocation for theassociated PSSCH in the current period and/or the resource reservationfor the next period.

For aperiodic traffic, PSCCH-1 indicates the resource allocation for itsassociated PSSCH.

The channel PSCCH-2 may be used to assist data decoding for theassociated PSSCH including the possible retransmissions, i.e. comprisetransmission format information for the associated data channel. ThePSCCH-2 may be multiplexed with associated PSSCH in FDM (similarly toPSCCH/PSSCH in LTE R14/15) or in (intra-TTI) TDM (similarly toNR-PDCCH/PDSCH in NR R15).

SCI is exclusively divided into SCI-1 and SCI-2. That is, SCI-1 andSCI-2 comprise different sidelink control information. SCI-1 is carriedby the first control channel, while the second control channel canconvey SCI-2 only, or convey both SCI-1 and SCI-2. That is, the methodmay comprise providing the first control information and the secondcontrol information using the second control channel. In this case, thesecond control channel conveys all the relevant sidelink controlinformation.

When the second control channel comprises SCI-2 only, the receiverdecodes both PSCCH-1 and PSCCH-2 before it decodes PSSCH for the datapacket.

In the case where the second control channel conveys both SCI-1 andSCI-2, the receiver may decode PSSCH for the data packet if it firstdecodes at least PSCCH-2.

At least one of the first control information and the second controlinformation may comprise at least one of data packet retransmissioninformation and demodulation reference configuration information for theassociated data channel.

In an example embodiment, PSCCH-1 comprises the carried SCI-1 and DMRS.The PSCCH-1 may convey information explicitly (e.g. the informationincluded in SCI-1) or implicitly (e.g. the information indicated throughdifferent DMRS sequences) depending on the specific design of thePSCCH-1 channel.

PSCCH-1 may convey SCI-1 for indication of resourceallocation/reservation information.

The first control information comprises at least one of an indication ofdata periodicity, data packet information indicating quality of servicerequirement, resource reservation information and resource allocationinformation.

That is, SCI-1 may include sidelink control information elements such aspacket QoS-relevant information including one or more of priority,latency requirement, and reliability requirement. For example packetQoS-relevant information may comprise packet priority with 3 bits,indicating the priority level of the associated data packet.

SCI-1 may comprise an indication of periodicity, e.g. 1 bit with 0indicating periodic traffic and 1 indicating one-shot aperiodic traffic.

SCI-1 may comprise an indication of resource allocation information e.g.7 bits, indicating the resource allocation in frequency e.g. the numberof allocated sub-channels.

PSCCH-1 may carry information indicating the presence of associated datafor periodic traffic. This may indicate that the associated data will beabsent in a current period but that the UE wishes to maintain theperiodic resource reservation in next period. PSCCH-1 may carry at leastone of a part or type of destination address e.g. 2 bits, indicatingpart or type of destination address to enable the receivers to decidewhether to proceed to decode the associated data to reduce receivingcomplexity for un-targeted receivers.

PSCCH-1 may comprise information on DMRS for PSCCH-2. E.g. implicitlyconveyed by the DMRS information used by PSCCH-1.

PSCCH-2 may convey SCI-2 for indication of transmission format ofassociated PSSCH.

The second control information comprises at least one of modulation andcoding scheme (MCS) information, multi-antenna transmission relatedinformation and destination address information.

SCI-2 may include modulation and coding scheme information (MCS) e.g. 5bits, indicating the MCS index used for the associated PSSCH datapacket.

SCI-2 may comprise retransmission information, e.g., retransmissionindex and time/frequency resource.

PSCCH-2 may carry MIMO-related information, indicating the multi-antennatransmission related information e.g. number of layers.

PSCCH-2 may carry at least part of destination address e.g. 8 bits, tosupport unicast/groupcast/broadcast.

PSCCH-2 may comprise DMRS information for associated PSSCH. Thisinformation may be carried implicitly or explicitly.

The method may comprise, when the associated data channel comprisesperiodic data traffic and there is no data transmission in a currentperiod, providing first control information using the first controlchannel, wherein the first control information comprises an indicationof the absence of data transmission in the current period. That is, forPSSCH with periodic traffic type, if a resource reservation has beenmade in a previous period but there is no data transmission in thecurrent period (e.g. due to congestion control), the UE may onlytransmit PSCCH-1, indicating the absence of associated data in thisperiod and reserve resource in next period.

The method may comprise, when the associated data channel comprisesperiodic data traffic and there is data transmission in a currentperiod, providing the second control channel or the first controlchannel and the second control channel with the associated data channel.That is, if a resource reservation has been made in previous period andthere is data transmission in the current period, a UE transmitsPSCCH-1, PSCCH-2 and PSSCH or PSCCH-2 and PSSCH (where the first controlinformation and the second control information are transmitted using thesecond channel). PSCCH-1 may multiplex in FDM with associated PSSCH andPSCCH-2 may multiplex in FDM and/or (intra-TTI) TDM with associatedPSSCH.

FIG. 7 and FIG. 8 illustrate examples of the proposed control channelstructure for periodic V2X traffic.

In the example shown in FIGS. 7 and 8, PSCCH-1 indicates that the datapacket type is periodic, which determines the interpretation of theinformation field of resource reservation in time as specified in Table1.

In the example shown in FIG. 7, the SCI information is exclusivelydivided into SCI-1 and SCI-2 (i.e. they have different controlinformation). PSCCH-1 indicates periodic traffic, resource reservationperiod and the presence or absence of associated PSCCH-2/PSSCH in thecurrent TTI.

In the example shown in FIG. 8, PSCCH-2 conveys SCI-1 as well as SCI-2.That is, PSCCH-2 conveys all the sidelink control information includingat least the resource reservation information and transmission formatinformation. PSCCH-1 indicates periodic traffic, resource reservationperiod and the absence of associated PSCCH-2/PSSCH in the current TTI.

Even for periodic traffic, the UE may abandon the packet transmission insome specific period e.g. due to reasons of congestion control based onmeasurements of CR/CBR. In this case, the UE transmits PSCCH-1 toindicate the resource reservation for next period. This may bebeneficial for channel sensing and resource selection of other UEs inthat those UEs could be aware of the resource reservation, instead ofrelying on the long-term energy measurement of S-RSSI over the periodicresources to exclude that resource. Since PSCCH-1 only occupies limitedresource (e.g. one PRB over one slot), the interference it brings to thesidelink transmissions (if any) may be limited.

The method may comprise, when the associated data channel comprisesaperiodic data traffic, providing the first control channel in timeresources preceding the associated data channel.

That is, for PSSCH with aperiodic traffic type, a UE transmits PSCCH-1,PSCCH-2 and associated PSSCH, where PSCCH-1 precedes PSCCH-2 and PSSCHin the time domain and PSCCH-2 could multiplex in FDM and/or (intra-TTI)TDM with associated PSSCH.

PSCCH-1 indicates the resource allocation of the associated PSSCH. WithPSCCH-1 transmitted before the associated data which is conveyed byPSSCH, the UE which has higher priority data to transmit may use thePSCCH-1 to preempt the low priority data transmissions of other UEs andtrigger them to make resource reselections or abandon theirtransmission.

FIG. 9 and FIG. 10 illustrate an example of the proposed control channelstructure used for aperiodic V2X traffic. When an aperiodic packet (e.g.an event-driven one-shot transmission packet) arrives from higher layerto MAC/PHY layers to be transmitted, based on the available channelsensing results and the latency requirement for the packet, the UEselects sidelink resource(s) for transmission of the packet (i.e. thepacket denoted by the grey rectangle). In order to prevent other UEs(with periodic or aperiodic traffic) from using this resource, the UEwill transmit PSCCH-1 ahead of the selected resource to indicate theresource reservation. Note that PSCCH-1 also carries the packetQoS-relevant information, which may be taken into account by other UEsin their resource selection/pre-emption related operations.

The PSCCH-1 indicates that the packet type of aperiodic traffic whichwill determine the interpretation of the information field of resourcereservation in time as specified in table 1.

In FIG. 9, the SCI information is exclusively distributed to SCI-1 andSCI-2 (i.e. they contain different control information) carried byPSCCH-1 and PSCCH-2 respectively. In this case, the resourcecorresponding to PSCCH-1 position in the TTI of PSSCH could be keptunused as shown in the figure. This may facilitate other PSCCH-1transmissions from other UEs.

In FIG. 10, PSCCH-2 conveys SCI-1 as well as SCI-2. That is, PSCCH-2conveys all the sidelink control information including at least theresource reservation information and transmission format information.The benefit of this configuration is that the receivers could stilldecode the PSSCH based on PSCCH-2 even if they miss the transmission ofPSCCH-1.

An example of the configuration of the resource reservation in time isshown in Table 1. Note that TU denotes time unit e.g. slot, TTI orsubframe.

TABLE 1 Time offset between PSCCH-1 and PSSCH Resource reservationReservation period for for one-shot aperiodic in time (4 bits) periodictraffic traffic 0000 No reservation 0 (i.e. same TTI for PSCCH-1/PSCCH-2/PSSCH) 0001 10 ms 1 TU 0010 20 ms 2 TUs 0011 50 ms 3 TUs 0100100 ms 4 TUs 0101 200 ms 5 TUs 0110 300 ms 6 TUs 0111 400 ms 7 TUs 1000500 ms 8 TUs 1001 600 ms 9 TUs 1010 700 ms 10 TUs 1011 800 ms 11 TUs1100 900 ms 12 TUs 1101 1000 ms 13 TUs 1110 Reserved 14 TUs 1111reserved 15 TUs

It should be understood that the apparatuses may comprise or be coupledto other units or modules etc., such as radio parts or radio heads, usedin or for transmission and/or reception. Although the apparatuses havebeen described as one entity, different modules and memory may beimplemented in one or more physical or logical entities.

It is noted that whilst the example embodiments have been described inrelation to, similar principles can be applied in relation to othernetworks and communication systems where periodic and aperiodic datatransmissions are supported. Therefore, although certain embodimentswere described above by way of example with reference to certain examplearchitectures for wireless networks, technologies and standards,embodiments may be applied to any other suitable forms of communicationsystems than those illustrated and described herein.

It is also noted herein that while the above describes exampleembodiments, there are several variations and modifications which may bemade to the disclosed solution without departing from the scope of thepresent invention.

In general, the various example embodiments may be implemented inhardware or special purpose circuits, software, logic or any combinationthereof. Some aspects of the invention may be implemented in hardware,while other aspects may be implemented in firmware or software which maybe executed by a controller, microprocessor or other computing device,although the invention is not limited thereto. While various aspects ofthe invention may be illustrated and described as block diagrams, flowcharts, or using some other pictorial representation, it is wellunderstood that these blocks, apparatus, systems, techniques or methodsdescribed herein may be implemented in, as non-limiting examples,hardware, software, firmware, special purpose circuits or logic, generalpurpose hardware or controller or other computing devices, or somecombination thereof.

The example embodiments of this invention may be implemented by computersoftware executable by a data processor of the mobile device, such as inthe processor entity, or by hardware, or by a combination of softwareand hardware. Computer software or program, also called program product,including software routines, applets and/or macros, may be stored in anyapparatus-readable data storage medium and they comprise programinstructions to perform particular tasks. A computer program product maycomprise one or more computer-executable components which, when theprogram is run, are configured to carry out example embodiments. The oneor more computer-executable components may be at least one software codeor portions of it.

Further in this regard it should be noted that any blocks of the logicflow as in the Figures may represent program steps, or interconnectedlogic circuits, blocks and functions, or a combination of program stepsand logic circuits, blocks and functions. The software may be stored onsuch physical media as memory chips, or memory blocks implemented withinthe processor, magnetic media such as hard disk or floppy disks, andoptical media such as for example DVD and the data variants thereof, CD.The physical media is a non-transitory media.

The memory may be of any type suitable to the local technicalenvironment and may be implemented using any suitable data storagetechnology, such as semiconductor based memory devices, magnetic memorydevices and systems, optical memory devices and systems, fixed memoryand removable memory. The data processors may be of any type suitable tothe local technical environment, and may comprise one or more of generalpurpose computers, special purpose computers, microprocessors, digitalsignal processors (DSPs), application specific integrated circuits(ASIC), FPGA, gate level circuits and processors based on multi coreprocessor architecture, as non-limiting examples.

Example embodiments of the inventions may be practiced in variouscomponents such as integrated circuit modules. The design of integratedcircuits is by and large a highly automated process. Complex andpowerful software tools are available for converting a logic leveldesign into a semiconductor circuit design ready to be etched and formedon a semiconductor substrate.

The foregoing description has provided by way of non-limiting examples afull and informative description of the exemplary embodiment of thisinvention. However, various modifications and adaptations may becomeapparent to those skilled in the relevant arts in view of the foregoingdescription, when read in conjunction with the accompanying drawings andthe appended claims. However, all such and similar modifications of theteachings of this invention will still fall within the scope of thisinvention as defined in the appended claims. Indeed, there is a furtherexample embodiment comprising a combination of one or more exampleembodiments with any of the other example embodiments previouslydiscussed.

What is claimed is:
 1. An apparatus comprising: at least one processor;and at least one memory including computer program code, the at leastone memory and the computer program code configured to, with the atleast one processor, cause the apparatus to at least: provide firstsidelink control information using a first sidelink control channel andat least second sidelink control information using a second sidelinkcontrol channel, wherein the first sidelink control informationcomprises at least an indication of resource allocation for anassociated physical sidelink shared channel, wherein data traffic istransmitted over the associated physical sidelink shared channel, andwherein the second sidelink control information comprises at leastinformation for decoding of the associated physical sidelink sharedchannel.
 2. The apparatus of claim 1, wherein the at least one memoryand the computer program code are further configured to, with the atleast one processor, cause the apparatus to at least: provide the firstsidelink control information and the second sidelink control informationusing the second sidelink control channel.
 3. The apparatus of claim 1,wherein the associated physical sidelink shared channel comprisesperiodic or aperiodic data traffic, and wherein the first sidelinkcontrol information comprises at least one of an indication of dataperiodicity and a quality of service requirement.
 4. The apparatus ofclaim 1, wherein the second sidelink control information comprises atleast one of modulation and coding scheme (MCS) information,multi-antenna transmission related information and destination addressinformation.
 5. The apparatus of claim 1, wherein at least one of thefirst sidelink control information and the second sidelink controlinformation comprises at least one of data packet retransmissioninformation and demodulation reference configuration information for theassociated physical sidelink shared channel.
 6. The apparatus of claim1, wherein the at least one memory and the computer program code arefurther configured to, with the at least one processor, cause theapparatus to at least: when the associated physical sidelink sharedchannel comprises periodic data traffic and there is no datatransmission in a current period, provide first sidelink controlinformation using the first control channel, wherein the first sidelinkcontrol information comprises an indication of the absence of datatransmission in the current period.
 7. The apparatus of claim 1, whereinthe at least one memory and the computer program code are furtherconfigured to, with the at least one processor, cause the apparatus toat least: when the associated physical sidelink shared channel comprisesperiodic data traffic and there is data transmission in a currentperiod, provide the second control channel or the first control channeland the second control channel with the associated physical sidelinkshared channel.
 8. The apparatus of claim 1, wherein the at least onememory and the computer program code are further configured to, with theat least one processor, cause the apparatus to at least: when theassociated physical sidelink shared channel comprises aperiodic datatraffic, provide the first control channel in time resources precedingthe associated physical sidelink shared channel.
 9. An apparatuscomprising: at least one processor; and at least one memory includingcomputer program code, the at least one memory and the computer programcode configured to, with the at least one processor, cause the apparatusto at least: receive first sidelink control information using a firstsidelink control channel and at least second sidelink controlinformation using a second sidelink control channel, wherein the firstsidelink control information comprises at least an indication ofresource allocation for an associated physical sidelink shared channel,wherein data traffic is transmitted over the associated physicalsidelink shared channel, and wherein the second sidelink controlinformation comprises at least information for decoding of theassociated physical sidelink shared channel.
 10. The apparatus of claim9, wherein the at least one memory and the computer program code arefurther configured to, with the at least one processor, cause theapparatus to at least: receive the first sidelink control informationand the second sidelink control information using the second controlchannel.
 11. The apparatus of claim 9, wherein the associated physicalsidelink shared channel comprises periodic or aperiodic data traffic,and wherein the first sidelink control information comprises at leastone of an indication of data periodicity and a quality of servicerequirement.
 12. The apparatus of claim 9, wherein the second sidelinkcontrol information comprises at least one of modulation and codingscheme (MCS) information, multi-antenna transmission related informationand destination address information.
 13. The apparatus of claim 9,wherein at least one of the first sidelink control information and thesecond sidelink control information comprises at least one of datapacket retransmission information and demodulation referenceconfiguration information for the associated physical sidelink sharedchannel.
 14. The apparatus of claim 9, wherein the at least one memoryand the computer program code are further configured to, with the atleast one processor, cause the apparatus to at least: when theassociated physical sidelink shared channel comprises periodic datatraffic and there is no data transmission in a current period, receivefirst sidelink control information using the first channel, wherein thefirst sidelink control information comprises an indication of theabsence of data transmission in the current period.
 15. The apparatus ofclaim 9, wherein the at least one memory and the computer program codeare further configured to, with the at least one processor, cause theapparatus to at least: when the associated physical sidelink sharedchannel comprises periodic data traffic and there is data transmissionin a current period, receive the second control channel or the firstcontrol channel and the second control channel with the associatedphysical sidelink shared channel.
 16. The apparatus of claim 9, whereinthe at least one memory and the computer program code are furtherconfigured to, with the at least one processor, cause the apparatus toat least: when the associated physical sidelink shared channel comprisesaperiodic data traffic, receive the first control channel in timeresources preceding the associated physical sidelink shared channel. 17.A method comprising: providing first sidelink control information usinga first sidelink control channel and at least second sidelink controlinformation using a second sidelink control channel, wherein the firstsidelink control information comprises at least an indication ofresource allocation for an associated physical sidelink shared channel,wherein data traffic is transmitted over the associated physicalsidelink shared channel, and wherein the second sidelink controlinformation comprises at least information for decoding of theassociated physical sidelink shared channel.
 18. A method comprising:receiving first sidelink control information using a first sidelinkcontrol channel and at least second sidelink control information using asecond sidelink control channel, wherein the first sidelink controlinformation comprises at least an indication of resource allocation foran associated physical sidelink shared channel, wherein data traffic istransmitted over the associated physical sidelink shared channel, andwherein the second sidelink control information comprises at leastinformation for decoding of the associated physical sidelink sharedchannel.
 19. A computer readable medium comprising a non-transitorycomputer-readable storage medium storing program instructions forcausing an apparatus to perform at least the following: providing firstsidelink control information using a first sidelink control channel andat least second sidelink control information using a second sidelinkcontrol channel, wherein the first sidelink control informationcomprises at least an indication of resource allocation for anassociated physical sidelink shared channel, wherein data traffic istransmitted over the associated physical sidelink shared channel,wherein the first sidelink control information further comprises anindication of whether the data traffic is periodic or aperiodic, andwherein the second sidelink control information comprises at leastinformation for decoding of the associated physical sidelink sharedchannel.
 20. A computer readable medium comprising a non-transitorycomputer-readable storage medium storing program instructions forcausing an apparatus to perform at least the following: receiving firstsidelink control information using a first sidelink control channel andat least second sidelink control information using a second sidelinkcontrol channel, wherein the first sidelink control informationcomprises at least an indication of resource allocation for anassociated physical sidelink shared channel, wherein data traffic istransmitted over the associated physical sidelink shared channel, andwherein the second sidelink control information comprises at leastinformation for decoding of the associated physical sidelink sharedchannel.